I´m not particularly keen on graffiti. So, I don´t have an exact idea about it. But, under my point of view it can be Art or vandalism depending on the way and the place where they are painted. It´s the same as with any kind of Art.
The common Graffiti we usually see on the walls, along the roads, around the towns or cities are names, words or simply letters that I personaly don´t like at all and which most of the time I associate to vandalism because they are dirtying and defacing some houses´ walls and public places. However, I have to say that sometimes I´ve seen Graffitis that were real masterpieces, more than some pictures that are in some exhibitions, like a dot in the middle of a white canvas.
Graffiti authors can be Art students, people fond of painting, creative and imaginative people or simply somebody with a spray in his hands. Some of them use their Graffiti to transmit messages, others to complain or criticize something, others to express their feelings as any other kind of artist. But, those who just use this style of art to enjoy themselves by using any place without respect for anybody or anything, aren´t artists at all. That´s vandalism. Therefore, it shouldn´t be allowed.
Art, in my opinion, is a large and abstract concept with many exceptions, difficult to define , with ingredients like creativity and imagination mainly, but also our knowledge of it plays an important part, although not indispensable in all of cases. For all of that, it´s impossible to set rules to consider what Art is or what Art is not.
Definitely, Graffiti could be considered Art because it´s a particular kind of artistic expression that isn´t represented anywhere else, I think, at the moment...
(Conchi del Nogal)

Art and graffiti
Reverse graffiti is a bold and provocative initiative, but at the same time I think it is an unusual experience. The idea of finding dirty surfaces and turning them into striking images or messages implies a kind of commitment with your neighbourhood or city and it might be considered positive in some way.
Sadly, a large number of graffitis are worthless as an artistic expression and they are an expensive problem for public services, councils and owners. Repetitive signatures everywhere, simple or childish drawings may be a type of expression, but above all they are vandalism.
I recognize that the process of becoming a good artist painting graffiti necessarily needs a yobbish period , practicing in forbidden places and taking criminal risks. I don’t try to deny graffiti its status because I am convinced that it is a kind of pop art which shows problems, feelings, needs and frustrations of young people. However, they are usually not concerned about the damages they cause and they are not respectful of the others .
On the other hand, I assume that achieving recognition as an urban artist is probably a hard way and undoubtedly, nowadays graffitis are integrated in our modern cultural demonstrations and frequently imitated; for example, in large canvasses covering the front of buildings while they are restored.
Coming back to the problems generated by this urban art, I deem that it is necessary to reach an agreement between artists an owners in order to be allowed to make this artistic work in a private property. It is not an original idea. Some councils let these artists do their work in specific areas and respecting some conditions. Even companies, sometimes hire them to decorate walls, vehicles or design logos.
To conclude, graffiti is a controversial expression of pop art which provokes sometimes admiration and sometimes a deep irritation.

(Joaquin Castro)